Photoelectric proximity fuse mounting



Dec. 25, 1962 CLARK 3,070,017

PHOTOELECTRIC PROXIMITY FUSE MOUNTING Filed Oct. 21, 1943 26 27 Q 34 I Fly 25 2a 2/ a I a6 a? 42 /4 32 4/ a8 a? Fzy 2;

WITNESSES: I I INVENT'OR 5 M tar/mm.

ATTORNEY 3,fi7ii,017 PHOTGEEZECTRI PROXllviliTY FUSE MOUNTING Earl K. Clark, Mansfield, Ohio, assignor, by mesne assignments, to the United States of America as represented by the Elecretary of the Navy Fiied Oct. 21, 1943, Ser. No. 597,123 1 Qiaim. (Cl. 102-793) My invention relates to a weapon and, more particularly, to a projectile for anti-aircraft use.

Projectiles fired at moving aircraft whether from antiaircraft batteries or from other airplanes as by means of rocket propulsion or other means seldom score a direct hit. It is, therefore, highly important that the projectile at least explode in the proximity of the target that is armed to be destroyed. When a projectile is fired from a moving aircraft at another moving aircraft, it is, of course, substantially impossible from the standjoint of the time elements involved to calculate the range, even though it be done with mechanical devices, and at the same time set the range for the explosion of the projectile. I, therefore, propose that instead of providing complicated range adjusting means and range calculating means to utmze a projectile which is provided with a photoelectric cell, commonly known as an electric eye, and a suitable optical system for sighting the target. I

One object of my invention is to provide a pro ectile which will explode when the target holds a definite position with respect to the moving projectile.

Another object of my invention is the provisionof a deefnse weapon which senses the proximity of a target.

A more specific object of my invention is the combination of an optical system in the ogival surface of a projectile for optically scanning the region in the direction of movement of the projectile and the provision of means for exploding the projectile when the target comes into a certain viewing position of the projectile.

Other objects and advantages will become more apparent from a study of the following specification and the accompanying drawings, in which:

FIGURE 1 is a longitudinally sectional view of a projectile constructed in accordance with my invention shown substantially in full-size scale; and

FIG. 2 illustrates a relation of the optical system to the electrical system and the chain of explosives actuated by the system.

in H6. 1, 1 designates the main body of the projectile having the ogival surface 2. Within this housing the main explosive charge is contained in the regions 3 and 4, which explosive charge is to be exploded when the target is in a given position with reference to the projectile. Within this housing, I position a container or can 5 having a lower compartment 6 containing the tetryl charge, a larger compartment 7 disposed above compartment 6 for housing the batteries 8, 9, it etc., shown in FIG. 2. Above the compartment 7 I provide an amplifier housing 14 in the assembled condition rigidly disposed with reference to the container 5 and the projectile housing 1. The amplifier housing is rigly mounted on the housing 1 of the projectile by threads 15 and the lens supporting base 16 is brazed to the upper rim 17 of the amplifier housing at the circuferential region 18. Brazing is resorted to to prevent any moisture from entering the projectile. The base 16 is bent back upon itself inwardly at 19 so as to form a supporting ledge 26 for the lens 21 and the photoelectric cell 22. A suitable disk or washer-like member 23 of insulating material is riveted to the shoulder 20, and the lens 21 is screw-threaded into the insulating member 23. A nose bracket 24 is attached to the upper face of the lens by means of four screws 25, and a spring 26 is disposed between the photocell 22 and the underside of the nose bracket. This s pring is under suitable compression lifillfifill? Patented Dec. 25, it??? and thus operates to properly seat the photoelectric cell in the insulating member 23. A nose cap 27 is assembled by threaded engagement with nose bracket 24 and seats on a. shoulder provided on the lens 21. Water-proofing cement is disposed between the nose cap 27 and the lens 21 at region 28, and, similarly, water-proofing cement is disposed on the entire engaging surface between the lens and the base 16, thus preventing any water or other material from penetrating the interior of the unit.

All the electrical corponents except the batteries are assembled on the amplifier panel 3i. This assembly is attached to the terminal plate 32 by means of two pins 33. The order of assembly of my unit which is an important feature of safety is as follows: After the completion of a cylindrical supporting base 34 composed of a plurality of rims or rings as 17, 35, 36, and 37, the base 16 for the lens is brazed to the ring 17, thus forming the amplifier housing. Actually the member 34 is a unitary structure when completed, but for reasons which appear more clearly in a copending application of William J. Russel, Serial No. 507,190, filed October 21, 1943, now Patent No. 2,449,511 directed particularly to the can construction, this element 34 is shown as composed of a plurality of rings. The insulating member 23 is then riveted into place. The amplifier unit is mounted on the terminal plate 32 and the panel 31 is positioned from below into the member 34. It will be noted that the terminal plate 32 is of suificient diameter to seat on the shoulder 38. To hold the amplifier unit in place, the lower edge of the member 34 or, more specifically, the ring 37 is spun inwardly at 39 to firmly hold the amplifier unit in position. The photocell is then positioned on the insulating member 23 and suitable connections made with the amplifier. The lens is screwed into position to firmly hold the photocell in its seat after which the nose piece is screwed into position. Thereafter the cap 27 is placed in position. To hold all the elements of the rather delicately built amplifier system in place, the region within the amplifier chamber when the foregoing assembly has been made is then filled with a potting material through a hole 49 in the terminal plate 32. This hole 40 may be provided with a suitable screw plug to prevent any escape of the potting material if it should become fluid or semifiuid as when these devices have to be stored prior to use in such places as munition dumps disposed in a hot desert region. The terminal plate is provided with the terminal members ll for connecting the amplifier to the batteries and to provide a suitable water-tight cell between the can 5 and the amplifier chamber and the battery compartment. I position a rubber or neoprene gasket 42 between the battery supporting base, not shown, and the spun-over region 39 of the amplifier housing. This rubber gasket has certain special uses more clearly shown in my copending application Serial No. 507,124, filed October 21, 1943 now Patent No. 2,439,923. In positioning the can 6 into place, it is first pushed upwardly and screw-threaded to the mem 'ber 34 at the screw-threaded region shown at 43. While all these assemblies are being rnade, the tetryl chamber 6 is open, and the tetryl charge is not in position since the plate 44 is not in the position shown. amplifier housing and optical system and the can 6 are actually to be placed in the projectile housing 1, the tetryl charge is placed in position in chamber 6, and the plate 44 is slipped into place against the shoulder formed at the end of the inverted cup-like member 45, and the lower end of the can 5 is then spun over at 46 to hold the plate in position.

In FIG. 2, which is somewhat schematic and does not purport to show every detail of the actual amplifier circuit used, since it does not in itself constitute part of my invention, I show the amplifier actuated squib 47 in relation to the fuse cap 48. This fuse cap will be disposed Only when the directly above chamber 6 and at the opening 49. It Will thus be apparent that any accidental firing of the squib 47 will not set oif the tetryl charge since in my design th tetryl charge is not in position except when the entire unit is actually to be positioned in the housing 1 of the projectile. Any careless handling of my unit will thus involve the discharge only of the squib 47 and the cap 48 without setting off the highly dangerous tetryl charge.

*rorn the foregoing description, it will be apparent that I have provided a unit of low cost sheet metal fabrication that may be manufactured with materials having a low priority and with tools requiring no special design but of the type found in any factory. Furthermore, I have provided a unit that is light in Weight as compared with similar equipment made from cast material. Furthermore, I have provided the utmost protection for the circular lens, the lens being firmly housed within the base 16 and protected by the cap 27 and the light gathering surface being so dispozed that it is slightly below the ogival surface of the projectile. Any handling of the unit 01 the completed projectile or any storage of the projectile adjacent other projectiles or objects will not cause marring or otherwise destroy the light gathering properties of the exposed portion of the lens. In actual design, the light gathering surface of the lens is so positioned that the lens has a look forward angle with reference to a plane normal to the direction of Eight of the projectile of 22 /2". This angle itself may be, of course, varied, depending upon the known velocity of the projectiles. I prefer to apply an opaque covering, such as paint, to all parts of the annular lens except the outer light gathering surface and the interior annular focal surface adjacent the photo-electric cell 22, in order to minimize transmission of light rays other than those directed at the preselected angle just mentioned. Propelled at a very high velocity and used against targets having a high velocity might require a greaterlook forward angle since it must be considered that some time may be required from the time the target is sighted until the full explosion takes effect.

The light gathered by the light gathering surface is focused on the photocell, and the adjustment is such that the photocell is responsive to ordinary sky light and is not adversely affected by direct sunlight i.e., the photoelectric apparatus will be conditioned either in the rays of the sun or by daylight of lesser intensity-than that of direct sunlight for preventing ignition of the fuse of the projectile until a target is viewed through the lens. It will be understood that a projectile constructed according to my invention is not burdened with any auxiliary or self-contained source of light, but is adapted to be adjusted for automatic operation in response to a predetermined variation in the daylight rays collected by the lens and impinged on the photocell, such as a variation in daylight caused by the shadow of a target as the projectile ap proaches it. The adjustment of the electrical components is such that the photocell operates in response to variations in the intensity of the light transmitted to the photocell and the rate of change of such intensity. The apparatus thus senses the relative velocity between the target and projectile and a more expeditious explosion is effected with higher relative velocities.

While I have shown a specific construction and combination of elements, I do not wish to be limited to the particular showing made, but with to be limited only by the scope of the claim hereto appended.

I claim as. my invention:

in a bomb or projectile of the type having'photoelectrio-fuse control, the combination of a body structure having an ogival surface, housing means secured to the body structure, said housing means having an annular cover of sheet metal provided With an exterior surface conforming to the ogival contour of the bomb and an inner retrors'e flange portion, an annular lens secured in fixed relation within said flange portion of the cover, said lens having a light gathering surface failing just below the ogival surface, a nose bracket secured to the lens, a photoelectric 'cell'operatively reiated'to the fuse control of the bomb, a spring disposed'between the nose bracket and the cell to bias the cell to a fixed position to be subject to the light gathered and focused by the lens, a capsecured to the nose bracket and covering the nose bracket and part of'the lens at-the forward part up to the iorward edge of the light gathering surface, an opaque covering for the lens applied to all parts of the lens except the focal region and the light gathering surface, and means disposed at the regions of the lens in contact with the cap and cover for grevgnting any moisture or other fluid from entering the om References Cited in the file of this patent UNITED STATES PATENTS 7 

